Plastic casting machine



Nov. 24, 1942. LESTER 2,303,288

PLASTIC CASTING MACHINE Original Filed April 15, 1938 INVENTOR I NATHAN LESTER him 9 ATTORNEYS Patented Nov. 24, 1942 UNITED; STATES PFAT ENT. OFFICE PLASTIC GASTINGMACHINE 1 NathanTester, Cleveland, hio,,assignor to Lester Engineering Company, Cleveland, Ohio', at cor-Q [poration of Ohio Original application April 15, 1938, Serial No.

Divided. and this application Februlily-23, 1940, Serial No. 320,364 i I 2 Claims; o1 .'1's'-'-3o) The present application isa division of my co-pending application Serial :No. 202,301, filed April 15, 1938. v p The particular purpose of thepresent application is to provide means for simultaneously meastion of a machine embodying the invention.

Such machine comprises a supporting base,. a portion of whichisiindicated at l, mounting the vertically extending stationary .die plate 2 and the movable die plate 3. The mechanism for movably mounting the movable die plate v 3 upon the base I need not be further illustrated or described, since such mechanism is well known to those skilled in the art.

Die blocks 4 and v 5 mounted plates 2 and 3 respectively line 6 to form the die cavity]. p g

A pressure casting cylinder 8 is fixedly mountprinciple :of my upon the die ed in the stationary die plate 2. A second, hollow cylinder 9 is mounted within the casting cylinder 8. and its outer diameter is less than the inner diameter of the cylinder} so that there is a space between the walls of these two cylinders. This space is adapted to. be occupied.

by the reciprocable annular ram or plunger l0 whose extending portion Ill constitutes a. piston rod upon which the hydraulic piston I2 is mounted. The plunger l0 and its portion Ill are con.- nected by means of the threaded coupling II.

the single figure is a vertical sectional view illustrating the construcmeet at the parting packing gland or stuflingj box l8 seals the annu lar plunger portion, III with respect to the-fixed cylinder 9.- In this manner, the possibilityof any leakage of thehydraulic fluid from the cylinder l3 along the surfaces of the annular plunger portion l0 and of the fixed cylinder'9, asthe former reciprocates, is prevented. Y

A'material feed hopper l9is mounteclon the stationary die plate 2. A rotatablemeasuring cylinder is mounted in thecylindrical housing 2| immediately below the hopper H. The measuring cylinder 20, ,has a diametrically extending measuring cavity 22. A connecting rod 23 is eccentrically connected to the rotatable cylinder 20 at one end and connected at the other end by means of the bracket, to the annular plunger Ill. Reciprocation of the plunger I0 is thus adapted to move the rotatable cylinder 20 from an angular position of ;rotation wherein the upper, open end of themeasuring cavity'22 is in registry with the bottom opening 25 of the. hopper |9, to the alternate position where its lower Y open .end of the cavity:22 is in registry with the entrance end 26 of 'the material feed passage 21. The latter position of the rotatable cylinder 20 is shown in the drawing. The lower or discharge end 23 of the feed passage 21 communicates with the space between the casting cylinder} and the fixed inner cylinder} at a point adjacent, the end of the annular plunger to when thelatter is fully retracted or ready to begin its working stroke.

; The piston |2 operates in the hydraulic cylinder l3 which is stationarily mounted by means of the bracket I4 upon the base The right hand end of the cylinder 9 extends beyond the head end of the piston l2 and is fixedly supported in the head ii of the cylinder l3 by means of the flange l6.

A packing gland or stufling box seals the annular plunger portion II) with respect to the rod end of the hydraulic cylinder l3. Another A compressed air, conduit 29 is located in the cylindrical housing 2| at apoint adjacent the upper open end of the measuring cavity 22 when the latter is in material feeding position asv indicated in the drawing. The introduction of compressed air through the conduit 29 aids the force of gravity in completely evacuating the powdered;- granulated, or finely divided material from the cavity 22, through-the passage 2:, to the pressurecasting cylinderfl.

The left hand or discharge end of the pressure casting cylinder 8 communicates with the passages 30 leading to the die cavity 1. Longitudi nally slidable; bars 3| aremounted .the die block 5 and extend transverselythrough the passages 30. ,The bars 3| are of greater width than that ol passages 30, and hence are adapted to.- completely obstruct and shut oil the latter. The 3 bars 3| are connected through rack and gear mechanism (not shown) to the rock shaft 32. A lever arm 33 on the upper end of the rock shaft 32 is connected to the horizontally movable bar 34. The latter is operated either manually or me,-

a force any of the material out chanically, such as by connection to a hydraulic cylinder, to rotate the shaft I2 and thus move the bars ll in and out to open and close passages 30.

A heating element 35 is located within the hollow cylinder 9. A threaded plug 36 closes the left hand end of the hollow cylinder 9 and aids in retaining the heating element 35 therein. A-

second heating element 31 is mounted upon the outer wall of the cylinder 8. The necessary electrical or fluid conduits ,(such as steam line'tubing) for supplying ment 35 are of course hand portion of the hollow fixed cylinder to" the exterior of the machin The operation of the above described mechanism ing cylinder 8 and 30 are closed by'the bars the discharge passages 3|. After the proper and desired plasticizationof the material in the'cylinder 8, the "passages 30 are opened by-withdrawal the annular plunger ll 'is'further moved in a left hand direction to completely evacuate the material intothe die cavity 1'. The length of time; the temperature" and tion of pressure upon the materialin the casting cylinder 8 are'determined of course by the particular type of material to be cast.

After the plasticized material is injected under pressure in the diecavity land has become solidified therein either by a chilling action, asis the case in the use of thermo-plastic maerials, or by heating or curing action as, is the case in thermo setting materials,,the movable die plate 3 is moved to open position in the casting ejected in' the customary manner. In the meantinrejsince the annular plunger ill hasbeen moved to'the end of its working stroke, or to the full extent of its travel in a left hand direction with respect to the drawing, the rotatable cylinder has accordingly been moved to a position wherez the 2 isupper open end ofthe measuring cavity placed" in communication with the discharge opening of the hopper I! so that thecavity ll'thereby becomes filled with a measured amount of the material. The plunger I0 is then moved upon its return stroke to the position shown in the drawing where the parts of the machine are ready to repeat the cycle bfloperatio'n.

.It will thus be seen'that my abovesdescribed invention provides means for uniformly and efficiently heating the entire mass of the material to be cast-upon each cycle of operation, and that such materialis completely evacuated from the heating and casting cylinder so that no portion of such 'materialremains to be subjected. to a heat energy to the heating elecarried through the right is as follows: Assuming that the measuring; cavity 22 has received a charge of material from of the bars SI and greater amount of heat treatment than any other portion, thus insuring a resultant casting of uniform consistency and properties. f

Other modes of applying the principle of my invention may be employed instead of the one explained, change being made as regards the structure hereindisclosed, provided the means chine-having a casting cylinder and a reciprocable part operable to eject material from said cylinder, a hopper, a fluid pressure supply conduit; material, measuring means located at the .bottom of said hopper and movable back and forth between charging and discharging positions, said measuring means being connectible with said hopper only when in charging position for receiving a predetermined-charge of material, and connectible with said conduit only'when in discharging position, a closed passage leading from said measuring-means to said casting cylinder and connectible with saidmeasuring means only when in discharging position andactuating'means connected "to said reciprocable part and to said measuring means operable upon ejecting? movement of said part to move said measuring meansto chargingposition and'upoii return movement of saidpa'rt to move said measuring means simultaneously to discharging position and in registry with said conduit whereby pressurefrom the latter aids in forcing material from said" measuring means through said passage and into'said cylinder;

the initial applica v 2. "In combination with a pressure casting machine having a casting cylinder and a reciprocable part operable to eject material from said cylinder,- a hopper,- a pneumatic pressure conduit; material measuring means comprising a rotatable measuring cylinder having an open ended diametrically extendingcavity, a housing enclosing said measuring cylinder, said hopper and said conduit being'connected' to said housing adjacent its top; a closed passage leading from said housing adjacent its bottom and'diametrically opposite said conduit to said casting cylinder, the discharge end of said hopper, said conduit, and the entrance end of said passage all bein located in the inner wall of said housing adjacent said measuring cylinder, said measuring cylinder being rotatable back and forth between alternate positions wherein one endof said cavity registers with said discharge end and the other end of said cavity registers with said entrance end, a' lostmotion connecting means'between said reciprocable part and said measuring means operable upon ejecting movement of said part to move said cylinder to a position connecting said cavity with said discharge endfand upon return" movement of said part to move said cylinder 'to its other position connecting said cavity with said entrance'end and with said pressure conduit whereby material from said cavity is pneumatically forced through'said passage into said cylinder. i

' F NATHAN L'E'S'I'ER. 

